Nuclear Structure and Nuclear Astrophysical Processes

Nuclear Structure and

Nuclear Astrophysical Processes

Toshio Suzuki Nihon University

Italy-Japan, Milan

Nov. 20, 2012

○ New shell-model Hamiltonians with proper spin-isospin interaction with tensor forces

Successful description of spin-degree’s of freedom in nuclei Gamow-Teller (GT) and spin-dipole (SD) strengths,

magnetic moments and M1 transitions ＊important roles of tensor force

○ Electron capture reactions in stellar environments ・e-capture rates in ⁵⁶Ni, ⁵⁸Ni and ⁶⁰Ni

・synthesis of ⁵⁶Ni, ⁵⁸Ni in type-Ia supernovae

○ ν-nucleus reactions

・ν-¹²C and synthesis of ¹¹B in type-II supernova explosions ・ν-¹³C by solar neutrinos

・ν-⁵⁶Ni and synthesis of Mn in supernova explosions

○ β-decays of waiting-point nuclei at N=126 and r-process nucleosynthesis

n

n

NS

R-process:

Heavy Nuclei

8

8

Explo. Si-burn.

Fe-Co-Ni,

60Co, ⁵⁵Mn, ⁵¹V … Si

Layer

n-process:

6,7Li, ⁹Be, ^10,11B … np-process:

92Mo, ⁹⁶Ru ?

n-process

180Ta, ¹³⁸La, ⁹²Nb, ⁹⁸Tc … n-n Scattering near Proto-Neutron☆

n-Collective Flavor Oscillation

MSW resonance at r~10³ (g/cm³) n-Flavor Oscillation

Various roles of n’s in SN-nucleosynthesis

Kajino

1. New Shell-Model Hamiltonians in p-shell and Neutrino-Nucleus Reactions

p-shell（p-sd） Cohen-Kurath+Millener-Kurath → SFO [ p: CK (8-16)2BME, p-sd: MK, sd, p2-(sd)2: Kuo’s G-matrix]

Monopole terms in p1/2-p3/2 , T=0 enhanced：ΔV = -1.9 MeV SFO: Suzuki, Fujimoto, Otsuka, PR C67, 044302 (2003)

Systematic improvements in the description of magnetic moments, GT transitions in p-shell nuclei are obtained.

1 2 1 2

1 2

2 1

2 1

T J

M

J

( J ) j j ;JT | V | j j ;JT V ( j j )

( J )

  

 





present = SFO Space: up to 2-3 hw Magnetic moments

tensor force

G-matrix vs phenom. interactions

Shell evolution in N=8 isotone

Otsuka, Suzuki, Fujimoto, Grawe, Akaishi, PRL 69 (2005)

6 8

Li Be B

B(GT) for ¹²C →¹²N ^{SFO*: gAeff/gA=0.95}

B(GT: 12C)_cal = experiment

SFO

PR C55, 2078 (1997)

Suzuki, Chiba, Yoshida,Kajino, Otsuka, PR C74, 034307, (2006).

HT: Hayes-Towner, PR C62, 015501 (2000)

NCSM: Hayes- Navratil-Vary, PRL 91 (2003) CRPA: Kolb-

Langanke-Vogel, NP A652, 91 (1999)

Inclusive = Exclusive (1

) + Excited state



3



Exp:

LSND PR C64 (2001)

2^－: g_A^eff/g_A = *0.75(MK2) *0.70 (SFO)

Cf. Gaarde et al.

q= 0.65 (CK)

Quenching of spin-dipole strength

2-

Nucleosynthesis processes of light elements

4 3

4 3

He( , 'p) H He( , 'n) He

n n n n

12 11

12 11

C( , 'p) B C( , 'n) C

n n n n

Enhancement of ¹¹B and ⁷Li abun- dances in supernova explosions Inner O/C He/C He/H H

7Be, 11Li abundance

SN Nucleosynthesis with Neutrino Oscillations

Supernova nucleosynthesis (n-process)

16.2 M star supernova model corresponding to SN 1987A

Increase by a factor of 2.5 and 1.4 Increase in the rates of charged-current reactions

4He(n_e,e^-p)3He and 12C(n_e,e^-p)11C in the He layer Normal mass hierarchy, sin²2q₁₃ = 0.01

10^-9 10^-8 10^-7 10^-6 10^-5

2 3 4 5 6

Mass Fraction

Mr / M

11B

11C

O-rich O/C He/C He/N

10^-10 10^-9 10^-8 10^-7 10^-6

2 3 4 5 6

Mass Fraction

Mr / M

7Be

7Li

O-rich O/C He/C He/N

no mix

no mix mix no mix

mix mix

out SN core

ν

3

2

ν

1

H-res

SN core out SN core

ν

3m

e

ν

2m

1m

Normal hierarchy

ν

2

1

3

ν

2m

e

ν

1m

3m

Inverted hierarchy

n

n

n

7

Li/

B Dependence on Mass Hierarchy and q

N(⁷Li)/N(¹¹B) Good indicator for neutrino oscillation parameters

normal

inverte no mix d

(Tne, Tne, Tnm,t, En)

= (3.2, 5.0, 6.0, 3.0) , (3.2, 4.8, 5.8, 3.0)

, (3.2, 5.0, 6.4, 2.4) , (3.2, 4.1, 5.0, 3.5) , (4.0, 4.0, 6.0, 3.0) , (4.0, 5.0, 6.0, 3.0)

(MeV, MeV, MeV, ×10⁵³ergs)

Including uncertainties

in neutrino temperatures

N(7Li)/N(11B) > 0.8

Normal mass hierarchy and sin²2

q

Possibility for constraining mass hierarchy and lower limit of the mixing angle

q

Neutrino experiments Constraining upper limit of q₁₃

Yoshida et al., PRL 96 (2006)

Supernova X-grain constraints

T2K, MINOS (2011)

Double CHOOZ sin²2θ＝０．１ Daya Bay, RENO (2012)

First Detection of ⁷Li/¹¹B in SN-grains

W. Fujiya, P. Hoppe, & U. Ott, ApJ 730, L7 (2011).

“Inverted Mass Hierarchy”

is statistically more preferred ! 74% ー Inverted

24% ー Normal

Mathews, Kajino, Aoki and Fujiya, Phys. Rev. D85,105023 (2012).

13C: attractive target for very low energy ν

(no contamonation of ¹²C below E_ν=15 MeV)

・ν-induced reactions on ¹³C

C ')

, (

C

N )

e , (

C

13 e

e 13

13 e

13

n n

n ^

GT transitions

Fukugita et al., PR C41 (1990) p-shell: Cohen-Kurath

g_A^eff/g_A =0.69

Detector for solar ν GT

GT

GT+IAS

p-sd shell: SFO

Solar ν cross sections

folded over ⁸B ν spectrum

2 43

2 43

2 42

2 42

e

cm 10

23 . 2 : SFO

cm 10

16 . 1 : CK

) M eV 69

. 3 2 (

) 3 ' , (

cm 10

34 . 1 : SFO

cm 10

07 . 1 : CK

)]

M eV 50

. 3 2 (

.) 3 s . g 2 (

[1 ) e , (



















 n

n





 n

Suzuki, Balantekin, Kajino, PR C 86, 015502 (2012).

2. New shell-model Hamiltonians in fp-shell and new

e-capture rates and ν-nucleues reactions cross sections:

GXPF1: Honma et al., PR C65 (2002); C69 (2004)

KB3: Caurier et al., Rev. Mod. Phys. 77, 427 (2005)

○ KB3G A = 47-52 KB + monopole corrections ○ GXPF1 A = 47-66

・ Spin properties of fp-shell nuclei are well described B(GT_-) for ⁵⁸Ni Fujita et al. g_A^eff/g_A^free=0.74

8-13MeV

M1 strength (GXPF1J) g_S^eff/g_S=0.75±0.2

KARMEN (DAR)

RQRPA vs Shell-model

SM(GXPF1J)+RPA(SGII) 259 x10 ^-42cm² RHB+RQRPA(DD-ME2) 263

RPA(Landau-Migdal force) 240 QRPA(SIII) 352 QRPA(G-matrix formalism) 174

56 56

Fe( n

, e )

Co

GT

Sasano et al.

PRL 107, 202501 (2011) f7/2 -> f5/2

f7/2 -> f7/2 f7/2 -> f5/2

e-capture rates in stellar environments

7 10 3

e

9 9

Y 10 10 g / cm T T 10 K

r 

 

ρY_e=10⁹

10⁸

10⁷

58Ni → ⁵⁸Co

Exp: Hagemann et al., PL B579 (2004) 60Ni → ⁶⁰Co

Exp: Anantaraman et al., PR C78 (2008)

Type-Ia supernova explosion

Accretion of matter to white-dwarf from binary star

→ supernova explosion when white-dwarf mass is over Chandrasekhar limit

→ ⁵⁶Ni (N=Z)

→ ⁵⁶Ni (e^-, ν) ⁵⁶Co Y_e =0.5 → Y_e < 0.5 (neutron-rich) → production of neutron-rich isotopes; more ⁵⁸Ni

Decrease of e-capture rate on ⁵⁶Ni → less production of ⁵⁸Ni.

e-capture rates:

GXPF1J < KB3G

←→

Y_e (GXPF1J) > Y_e (KB3G) Famiano

Problem of over-production of ⁵⁸Ni

GXPF1 -> ⁵⁸Ni/⁵⁶Ni decreases

58Ni

54Cr

54Fe

56Fe

Famiano, Otsuka, Kajino

●

Neutral current reaction on

Ni

B(GT)=6.2 (GXPF1J) B(GT)=5.4 (KB3G)

cf:

HW02 gamma p

n

p-emission x-sections increse

p-emission BR increses

59 58 59 59 59

Co : Ni(p, ) Cu(e , )^ n Ni(e , )^ n Co

Suzuki et al., PR C79 (2009)

OBS: Cayrel et al., Astron. Astrophys.

416 (2004)

Yoshida, Umeda, Nomoto

56 55 55 55 55

Ni( ,n n' p) Co, Co(e , )^ n Fe(e , )^ n Mn

Synthesis of Mn in Population III Star

54 55

Fe(p, ) Co

3. Beta Decays of N=126 Isotones and R-Process Nucleosynthesis

Focus on the 3

peak region

Waiting point nuclei

Moller, Pfeiffer, Kratz, PR C 67, 055802 (2003)

cf.

Q=g_A^eff/g_A=0.7, ε=2.0 (0^-)

Shell Model calculations

Neumann-Cosel et al, PRL 82 (1999) Q=g_s^eff/g_s=0.64: 2- in ⁹⁰Zr (e-scatt.)

r-process nucleosynthesis

Constant Entropy Wind Model L_ν=0.5x10⁵¹ erg/s

S=133 k_B (γ, e^-, e⁺) dm/dt=2.34x10^-6 M_sun

τ= 5.60 ms for T₉=5 ->T₉=2 T_9f=0.8

Neutrino processes on n, p and ⁴He are included

Half-lives:

Standard (Moller et al.) Modified

g_A^eff/g_A =0.34, g_V^eff/g_V =0.67 + ΔQ =1.0 MeV

Large quenchings are favored in A =206

(g_A^eff/g_A,g_V^eff/g_V)=(0.34,0.67), (0.51, 0.30), (0.47, 0.64)

Warburton, PR C 44, 233 (1991) PR C42, 2479 (1990)

Rydstrom, NP A512, 217 (1990)

S. Nishimura et al.

Summary

56 56

Fe(ne,e ) Co^

KARMEN (DAR)

Smaller e-capture rates

& larger (ν, ν’p) cross sections on 56Ni

Implications on nucleosynthesis smaller ratio for 58Ni/56Ni

larger 55Mn production

Shorter beta-decay half -lives at N=126 and Kr-Tc than FRDM

Summary

• A new shell model Hamiltonian SFO well

describes the spin responses in p-shell nuclei → new GT (SD) strengths in C isotopes and new ν-

C, ν-

C cross sections

Suzuki, Chiba, Yoshida,Kajino, Otsuka, PR C74, 034307, (2006).

Suzuki, Balantekin, Kajino, PR C 86, 015502 (2012).

• A new shell model Hamiltonian GXPF1J well

describes the spin responses in fp-shell niclei → new GT strengths in Ni isotopes which reproduce recent experimental data, ν-

Fe cross section

• Electron capture rates in

Ni,

Ni and

Ni are well described by GXPF1J.

→ Abundance ratio of

Ni/

Ni in type Ia supernova explosions is improved

・ New ν-nucleus reaction cross sections in

Ni → enhancement of production rates of Mn and Co in supernova explosions

Suzuki, Honma et al., PR C79, 061603(R) (2009)

・ Short half-lives for beta decays of N=126 isotones compared to a standard model (FRDM)

→ The 3

peak of the r-process element

abundances is shifted toward larger mass number region.

Suzuki, Yoshida, Kajino, Otsuka, PR C85, 015802 (2012)

Collaborators

M. Honma

,

T. Yoshida

, S. Chiba

, H. Mao

, K. Higashiyama

, T. Kajino

, T. Otsuka

B. Balantekin

, T. Umeda

, K. Nomoto

, Famiano

aUniversity of Aizu

bDepartment of Astronomy, University of Tokyo

cTokyo Institute of Technology ^dENSPS, Strasbourg

^eChiba Institute of Technology

fNational Astronomical Observatory of Japan

gDepartment of Physics and CNS, University of Tokyo ^hUniversity of Wisconsin

ⁱIPMU, ^jRIKEN